/*
 * Copyright (c) 2001-2006 JGoodies Karsten Lentzsch. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions are met:
 * 
 *  o Redistributions of source code must retain the above copyright notice, 
 *    this list of conditions and the following disclaimer. 
 *     
 *  o Redistributions in binary form must reproduce the above copyright notice, 
 *    this list of conditions and the following disclaimer in the documentation 
 *    and/or other materials provided with the distribution. 
 *     
 *  o Neither the name of JGoodies Karsten Lentzsch nor the names of 
 *    its contributors may be used to endorse or promote products derived 
 *    from this software without specific prior written permission. 
 *     
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, 
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */
package utils;

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsDevice;
import java.awt.PrintGraphics;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.RenderingHints.Key;
import java.awt.print.PrinterGraphics;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

/**
 * Utilities to install desktop rendering hints for correctly rasterizing texts.
 * 
 * @author Kirill Grouchnikov
 */
public class RenderingUtils {
    /**
     * Desktop property name that points to a collection of rendering hints. See
     * <a
     * href="http://java.sun.com/javase/6/docs/api/java/awt/doc-files/DesktopProperties.html"
     * >documentation</a> for more details.
     */
    private static final String PROP_DESKTOPHINTS = "awt.font.desktophints";

    /**
     * Installs desktop hints on the specified graphics context.
     * 
     * @param g2
     *            Graphics context.
     * @return Map of old rendering hints.
     */
    public static Map<Key, Object> installDesktopHints(Graphics2D g2) {
        Map<Key, Object> oldRenderingHints = null;
        Map<?, ?> desktopHints = desktopHints(g2);
        if (desktopHints != null && !desktopHints.isEmpty()) {
            oldRenderingHints = new HashMap<Key, Object>(desktopHints.size());
            RenderingHints.Key key;
            for (Iterator<?> i = desktopHints.keySet().iterator(); i.hasNext();) {
                key = (RenderingHints.Key) i.next();
                oldRenderingHints.put(key, g2.getRenderingHint(key));
            }
            g2.addRenderingHints(desktopHints);
        }
        return oldRenderingHints;
    }

    /**
     * Returns the desktop hints for the specified graphics context.
     * 
     * @param g2
     *            Graphics context.
     * @return The desktop hints for the specified graphics context.
     */
    private static Map<?, ?> desktopHints(Graphics2D g2) {
        if (isPrinting(g2)) {
            return null;
        }
        Toolkit toolkit = Toolkit.getDefaultToolkit();
        GraphicsDevice device = g2.getDeviceConfiguration().getDevice();
        Map<?, ?> desktopHints = (Map<?, ?>) toolkit
                .getDesktopProperty(PROP_DESKTOPHINTS + '.'
                        + device.getIDstring());
        if (desktopHints == null) {
            desktopHints = (Map<?, ?>) toolkit
                    .getDesktopProperty(PROP_DESKTOPHINTS);
        }
        // It is possible to get a non-empty map but with disabled AA.
        if (desktopHints != null) {
            Object aaHint = desktopHints
                    .get(RenderingHints.KEY_TEXT_ANTIALIASING);
            if ((aaHint == RenderingHints.VALUE_TEXT_ANTIALIAS_OFF)
                    || (aaHint == RenderingHints.VALUE_TEXT_ANTIALIAS_DEFAULT)) {
                desktopHints = null;
            }
        }
        return desktopHints;
    }

    /**
     * Checks whether the specified graphics context is a print context.
     * 
     * @param g
     *            Graphics context.
     * @return <code>true</code> if the specified graphics context is a print
     *         context.
     */
    private static boolean isPrinting(Graphics g) {
        return g instanceof PrintGraphics || g instanceof PrinterGraphics;
    }
}
